1. Field of the Invention
The present invention relates to a drive unit for driving a fuel pump for a small-sized vehicle using an electronic control unit (ECU).
2. Description of Background Art
A conceptual view of a drive unit for driving a fuel pump for a motorcycle is shown in FIG. 6. Referring to FIG. 6, gasoline is fed from a fuel tank 2 into a fuel pump 4 through a filter 3. The gasoline is pressurized in the fuel pump 4, and is fed into a fuel injector 6 through a filter 5.
The fuel pressure in an intake manifold 7 is maintained constant by a pressure regulator 8, and gasoline is fed into the fuel tank 2 through the pressure regulator 8, thus gasoline can circulate back to the fuel tank 2. A piston 21 is reciprocated along with the combustion of gasoline, to rotate a crank (not shown).
A power supply voltage is supplied from an on-vehicle battery 10 to the fuel pump 4. The fuel injection amount of the fuel injector 6 is controlled by an ECU (Electronic Control Unit) 9.
In the related art for motorcycles, the fuel pump 4 is driven such that a flow rate of gasoline passing through the fuel pump 4 is maximized irrespective of the fuel injection amount of the fuel injector 6.
In the case where a total current consumption of an electric system is large as in a four-wheeled vehicle, a ratio of the current consumption of the fuel pump to the total current consumption of the electric system becomes small.
Meanwhile, in the case where a total current consumption of an electric system is small, as in a motorcycle, a ratio of the current consumption of the fuel pump to the total current consumption of the electric system becomes large.
For this reason, it is expected to develop a drive unit for driving a fuel pump for a motorcycle, which is capable of reducing the current consumption of the fuel pump.
Further, it is expected to develop a drive unit for driving the fuel pump for a motorcycle, which prevents an injection amount of a fuel injector from being varied depending on a change in the power supply voltage of the fuel pump.